We wish to determine whether the normalizing effects of human leukemic lysozyme (HLL) on transformed human cells depend on the catalytic activity of the enzyme, or on its basicity, or on both features, or on neither. Selective chemical modifications of HLL will be carried out to: a) inactivate the enzyme without disturbing its structure or basicity, b) to neutralize the positive charge on the enzyme without destroying its enzymic activity, and various combinations of the foregoing will be applied. After preparation and characterization of the modified lysozymes, we will transmit them to our collaborator, E. Osserman, at Columbia University for testing in in vitro mammalian cell culture systems. The undersigned agrees to accept responsibility for the scientific and technical conduct of the project and for provision of required progress report if a grant is awarded as the result of this application.